+#ifdef KERNEL_LINUX
+int notify_upstart (void)
+{
+ char const *upstart_job = getenv("UPSTART_JOB");
+
+ if (upstart_job == NULL)
+ return 0;
+
+ if (strcmp(upstart_job, "collectd") != 0)
+ {
+ WARNING ("Environment specifies unexpected UPSTART_JOB=\"%s\", expected \"collectd\". Ignoring the variable.", upstart_job);
+ return 0;
+ }
+
+ NOTICE("Upstart detected, stopping now to signal readyness.");
+ raise(SIGSTOP);
+ unsetenv("UPSTART_JOB");
+
+ return 1;
+}
+
+int notify_systemd (void)
+{
+ int fd;
+ const char *notifysocket;
+ struct sockaddr_un su;
+ size_t su_size;
+ char buffer[] = "READY=1\n";
+
+ notifysocket = getenv ("NOTIFY_SOCKET");
+ if (notifysocket == NULL)
+ return 0;
+
+ if ((strlen (notifysocket) < 2)
+ || ((notifysocket[0] != '@') && (notifysocket[0] != '/')))
+ {
+ ERROR ("invalid notification socket NOTIFY_SOCKET=\"%s\": path must be absolute", notifysocket);
+ return 0;
+ }
+ NOTICE ("Systemd detected, trying to signal readyness.");
+
+ unsetenv ("NOTIFY_SOCKET");
+
+ fd = socket (AF_UNIX, SOCK_DGRAM, /* protocol = */ 0);
+ if (fd < 0) {
+ char errbuf[1024];
+ ERROR ("creating UNIX socket failed: %s",
+ sstrerror (errno, errbuf, sizeof (errbuf)));
+ return 0;
+ }
+
+ memset (&su, 0, sizeof (su));
+ su.sun_family = AF_UNIX;
+ if (notifysocket[0] != '@')
+ {
+ /* regular UNIX socket */
+ sstrncpy (su.sun_path, notifysocket, sizeof (su.sun_path));
+ su_size = sizeof (su);
+ }
+ else
+ {
+#if KERNEL_LINUX
+ /* Linux abstract namespace socket: specify address as "\0foo", i.e.
+ * start with a null byte. Since null bytes have no special meaning in
+ * that case, we have to set su_size correctly to cover only the bytes
+ * that are part of the address. */
+ sstrncpy (su.sun_path, notifysocket, sizeof (su.sun_path));
+ su.sun_path[0] = 0;
+ su_size = sizeof (sa_family_t) + strlen (notifysocket);
+ if (su_size > sizeof (su))
+ su_size = sizeof (su);
+#else
+ ERROR ("Systemd socket uses Linux abstract namespace notation (\"%s\"), "
+ "but I don't appear to be running on Linux.", notifysocket);
+ return 0;
+#endif
+ }
+
+ if (sendto (fd, buffer, strlen (buffer), MSG_NOSIGNAL, (void *) &su, (socklen_t) su_size) < 0)
+ {
+ char errbuf[1024];
+ ERROR ("sendto(\"%s\") failed: %s", notifysocket,
+ sstrerror (errno, errbuf, sizeof (errbuf)));
+ close(fd);
+ return 0;
+ }
+
+ close(fd);
+ return 1;
+}
+#endif /* KERNEL_LINUX */
+